Internal-combustion engine



W. P.MACDONALD. INTERNAL COMBUSTION ENGINE.

APPLICATION FILED AUG.6. 1920.

Patented Dec. 7, 1926.

PATENT OFFICE.

WILLIAM I. MACDONALD, 0F VANCOUVER, BRITISH COL'UMBIA, CANADA INTERNAL-COMBUSTION ENGINE.

i Specication of'Letters Patent.

Patented Dec. 7, 1920.

Application led August 6, 1920. Serial No. 401,610.

T 0 all whom t may concern.'

Be it known that I, WILLIAM P. MACDON- ALD, citizen of the Dominion of Canada, residing at Vancouver, in the Province of British Columbia, Canada, have invented certain new and useful Improvements in Internal-Combustion Engines, of which the following is a specification.

This invention relates to an internal combustion engine applicable to either two or four stroke cycle, the object of which is to provide for rapid expansion of the products of combustion with a relatively slow piston movement. A f

This desired object is attained by connecting a piston and a concentric piston sleeve to diametrically opposed cranks and by providing for admission, compressionand explosion of the charge between the oppositely connected piston and sleeve whereby the force of the explosion is expended to move them in opposite directions to rotate the shaft. v

The invention is fully described in the following specification, reference being made to the drawings by which it is accompanied, in which:

Figure 1 is a vertical longitudinal section.

Fig. 2, a vertical cross section through the lower part of the cylinder and crank casing, and

Fig. 3, a cross section on the line 8-3 in Fig. 1.

In these on the upper end of which is secured a cylinl der 8 vconcentric with the inner cylinder 2,-,

and on the upper end of 8 is secured a third concentric cylinder 9, relatively smaller than 8, the upper end of which is closed with a cover 10.

Fitting the cylinder 9 and inner cylinderl 2 is a double hollou7 piston 11, 12, the lower drawings represents the crank v casing in which the crank shaft 4 is sup- 4 end of which is connected by a rod 13 to the middle crank pin 3, and fitting the annular space between the cylinder 8 and the outside of the cylinder 2 is a sleeve piston 14, in the lower end of which are secured pins by which the sleeve piston is connected by rods 15 to the pins of the outer cranks 6.

The pin holding brackets of this piston sleeve are movable in slideways formed in the distance member 7 and sustain it against any inequality of thrust of the connecting rods tending to rotate the sleeve.

Each piston 11, 12 1s ring-packed, as is the outer bearing of the sleeve piston 14. The outside ofl the inner cylinders 2 is also ring-packed below the lower limit of the sleeve pistons movement on it.

When this construction is used in a two stroke cycle engine the intake from the carbureter is at 16 and the gas is delivered into the space between the hollow piston 11 and the cover 10, as the piston 11 moves downward. On the upward stroke the charge, indrawn at 17 and 18 is initially compressed, and as the piston 11 approaches the upper limit of its movement and uncovers the port 18 the charge as compressed by thatl piston is delivered through the ports 17 and 18, to the underside of the piston 1.1, that is, into the annular space between the piston 11 and the sleeve piston 14.

The initially compressed charge so delivered, is, during the next downward movement of the piston 11, compressed between it and the upwardly moving sleeve piston 14, and the finally compressed charge is ignited at the spark plug 20 midway between the piston 11 and the sleeve piston 14, the force of the explosion expending itself between the piston 11 moving upward and the sleeve piston 14 moving downward, the pressure .of the explosion thus exerting itself on the diametrically opposed cranks 5 and 6 to rotate the shaft 4 in one direction.

The exhaust port 21 is located in the wall of the cylinder 8 to be uncovered by the upper edge of the sleeve piston 14 as it approaches the lower limit of its movement the products of combustion being scavenged .through the exhaust port 21 by the incoming fresh charge through the port of 18, which charge is, as explained, partially compressed during the upward movement of the piston ll.

It will be noted that the area on which the explosive gases act on the piston 11 is substantially equal to the area on which they act on the sleeve piston 14, the bore of the cylinder 8 being as much larger than that of the cylinder 9 as will compensate for the cross section area of the wall of the inner cylinder 2.

As the explosion occurs between the receding piston and the sleeve piston a rapidly enlarging volume is provided for the expansion oi' the explosive gases. The construction also lends itself to a favorable means for obtaining a uniform and favorable ratio of compression. f

The same general construction of engine is applicable to a four stroke cycle with modifications in the inlet and exhaust ports and a mechanically operated control of the same.

These features rendering the construction suitable for a four stroke cycle engine will form the subject matter of a separate application.

Havin ventiom as new and desire to be ters Patent, is:

l. An internal combustion engine, comprising in combination, a crank case supporting a shaft having three cranks of equal throw, the middle crank being diametrically opposite the two other cranks, three concentric cylinders secured to and upwardly projecting from the crank case, a double piston endwise movable within the inner cylinder and within the one next larger, which piston is connected to the pin of the middle crank, a sleeve piston endwise movable between the outside of the inner cylinder and the bore of the largest cylinder, which sleeve is connected to the pins of the two outer cranks, means for admitting a gaseous charge to the space between the piston which moves in the cylinder of intermediate diameter and the sleeve piston, means for igniting that charge after compression of the same between said piston and sleeve whereby the pressure of the explosion is transmitted in opposite directions to the diametrically o posite cranks, and means for exhausting t e products 1 of combustion.

2. An internal combustion engine, comprising in combination, a crank case supporting a shaft having three cranks of equal throw, the middle crank being diametrically opposite the two outer cranks, three concentric cylinders secured to and upwardly projecting from the crank case, a double piston endwise movable within the inner cylinder and within the one next larger, which piston is connected to the pin of the middle now particularly described my inprotected in by Letcrank, a sleeve piston endwise movable behereby declare that what I claim.

tween the outside of the inner cylinder 'and the bore of the largest cylinder, which sleeve is connected to the pins of the two outer cranks, means for admitting a gaseous charge to the space between the piston which moves in the cylinder of intermediate diameter and the sleeve piston, means for igniting that charge after compression of the same between said piston and sleeve, means for exhausting the products of combustion, and means for scavenging the products of combustion with the inpassing charge admitted from the end of the cylinder opposite to the exhaust.

An internal combustion engine, comprising in combination, a crank case supporting a shaft having three cranks'of equal throw, the middle crank being diametrically opposite the two outer cranks, three concentric cylinders secured to and upwardly projecting from the crank case, a double piston endwise movable within the inner cylinder and within the one next larger which piston is connected to the pin of the middle crank, a sleeve piston endwise movable between the outside of the inner cylinder and the bore of the largest cylinder, which sleeve is connected to the pins of the two outer cranks, means for admitting a gaseous charge to the end of the cylinder of intermediate diameter which is farther from the crank shaft, means for compressing that indrawn charge between the piston and the cylinder cover,

means "for delivering the charge so com- Vscavenging 'the` cylinder with the next indrawn charge.

4. An internal combustion engine, comprising in combination, a crank case supporting a shaft having three cranks of equal throw, the middle crank being diametrically opposite the two outer cranks, an inner cylinder secured to and upwardly projecting from the crank case in alinement with the middle crank, a hollow distance piece secured to the crank case outsidelthe inner cylinder, a second cylinder secured to and upwardly projecting from the distance piece outside of and concentric with the inner cylinder, a third cylinder of relatively smaller diameter secured to and upwardly projecting from the second cylinder with which it is concentric, a cover closing the upper end of the third cylinder, a hollow stepped piston fitting the third cylinder and the bore of the inner cylinder, said piston connected to the pin of the middle crank, a sleeve piston endwise movable between the outside of the inner cylinder and the bore of the second cylinder, said sleeve piston connected to the outer cranks, means for admitting a gaseous 1,361,390 l i B charge between the cover of the third cylton is at the upper limit of its movement,

meansl for igniting the charge so admitted after compression of the same between the piston of the third cylinder and the sleeve piston, means for exhausting the products of combustion, and means for scavenging the 10 cylinder by the incoming next charge.

In testimony Whereot` I aix my slgnature.

` WILLIAM P. MACDONALD. 

